KR101891366B1 - Polymer composition for electrical devices - Google Patents

Abstract

The present invention relates to a polymer composition having improved electrical properties and, preferably, its use in electrical devices, and to a cable surrounded by one or more layers comprising said polymer composition.

Description

[0001] POLYMER COMPOSITION FOR ELECTRICAL DEVICES [0002]

The present invention relates to a polymer composition for producing a layer of an electric or communication device, preferably a cable, preferably a power cable, more preferably a direct current (DC) power cable; A cable, preferably a power cable, more preferably a direct current (DC) power cable, comprising a polymer composition and optionally crosslinkable and then crosslinked; And a method of manufacturing a cable.

Polyolefins are widely used in demanding polymer applications where polymers must meet high mechanical and / or electrical requirements. For example, in electric power cable applications, especially in medium voltage (MV), especially high voltage (HV) and ultra high pressure (EHV) cable applications, the electrical properties of polymer compositions are of considerable importance. In addition, important electrical properties may be different for different cable applications, such as for AC (AC) cable applications and for DC (DC) cable applications.

Cable Crosslinking

A typical power cable includes at least an inner semiconductor layer, an insulating layer, and a conductor surrounded by an outer semiconductor layer in that order. Cables are conventionally made by extruding layers on conductors. One or more of the polymeric materials of the layers are then typically crosslinked to improve, for example, the heat resistance and deformation resistance, creep properties, mechanical strength, chemical resistance and abrasion resistance of the polymer (s) of the layer (s) of the cable. In the cross-linking reaction of the polymer, inter-polymer cross-linking (cross-linking) is mainly formed. Crosslinking can be carried out using free radical generating compounds such as peroxides. A free radical generator is typically incorporated into the layer material prior to extrusion of the layer (s) onto the conductor. After forming the layered cable, the cable is subjected to a crosslinking step to initiate radical formation and thereby a crosslinking reaction.

Peroxides are very common free radical generating compounds used in the polymer industry for such polymer modification. The resulting decomposition products of peroxide may include volatile by-products, which are undesirable (because they can be dangerous and may have a negative effect on the electrical properties of the cable). Thus, for example, when diecumperoxide is used, volatile degradation products such as methane are typically reduced or removed to a minimum amount after the crosslinking and cooling steps. This removal step is generally known as the degassing step. The degassing step consumes a lot of time and energy and is therefore an expensive operation in the cable manufacturing process.

In addition, the cable production line used and the desired production rate can put restrictions on the cable material, especially when creating larger size power cables. In addition, the crosslinking rate and degree of crosslinking of the polymer in the cable layer are particularly favorable, for example, in the case of a chain type continuous vulcanization (CCV) line (especially for thicker structures), which is the type of vulcanization line well known in the art The cable should be sufficient to minimize or avoid any undesirable sagging problems that occur during cable generation.

Electric conductivity

DC electrical conductivity is an important material property, for example, for insulating materials for high voltage direct current (HV DC) cables. First, the strong temperature and electric field dependence of this property affects the electric field. The second problem is that heat is generated inside the insulating layer due to a leakage current flowing between the inner semiconductor layer and the outer semiconductor layer. This leakage current depends on the electric field and electric conductivity of the insulating layer. The high conductivity of the insulating material can even lead to thermal runaway under high stress / high temperature conditions. Therefore, the conductivity should be low enough to avoid thermal runaway.

Therefore, in the HV DC cable, the insulating layer is heated by leakage current. For a particular cable design, heating is proportional to the insulation layer conductivity x (electric field) ² . Therefore, as the voltage increases, more heat is generated.

There is a high demand for increasing the voltage of power cables, preferably direct current (DC) power cables, and therefore the need to find alternative polymer compositions with reduced conductivity is continuing. Such polymer compositions should preferably also have the excellent mechanical properties required for demanding power cable embodiments.

The present invention relates to a composition comprising (a) a polyolefin, (b) optionally a peroxide, if present, preferably present in an amount of less than -00-35 millimoles per kg of the polymer composition, and (c) .

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic partial cross-sectional view of two thin layers and an intervening layer therebetween, showing the usual lamellar structure of anion exchange additive preferred as ion exchange additive (b). The stable thin layer is shown as a continuous layer and the round shaped material shows the interchangeable anions of the intermediate layer.

Unexpectedly, the polyolefin (a) is combined with the ion exchange additive (c) as defined hereinbefore or hereinafter, and optionally with the peroxide (b) (e.g., well known dicumyl peroxide) , The electrical DC conductivity of the polymer composition is significantly reduced (i. E., Significantly less).

Without wishing to be bound by any theory, it is believed that the ion exchange additive (c) captures harmful anionic materials such as chlorine which may be present in an ionic material, for example, polyolefin (a), which worsens (increases) the electrical DC conductivity I think.

Thus, polymer compositions are highly desirable for electrical and communication applications, preferably for wire and cable applications, particularly power cable layers. In addition, the polymer compositions of the present invention may have an electrical characteristic that is represented by a reduced (i.e., low) electrical DC conductivity, such as to minimize undesirable heat generation in, for example, an insulating layer of a power cable, particularly a DC power cable. Thus, the present invention is particularly advantageous for cables.

The present invention also relates to a composition comprising (a) a polyolefin, (b) optionally a peroxide, if present, preferably present in an amount of less than -00-35 millimoles per kg of the polymer composition, and (c) Or a polymer composition as defined below, for producing an electrical or communication device comprising said polymer composition, preferably an electrical or communication device. Such devices are, for example, cables, connections, including termination load connections in cable applications, capacitor films, and the like. The most preferred use of the present invention is the use of the polymer composition to produce a layer of cable.

The polymer compositions of the present invention are hereinafter also abbreviated herein as "polymer compositions ". The components thereof as defined above are also abbreviated herein as "polyolefin (a)", "peroxide (b)" and individually "ion exchange additive (c)". The expression "amount of less than 35 millimoles-O-O per kg polymer composition" means that the peroxide is present, i.e., a specific amount of peroxide is added to the polymer composition.

Preferably, the polymer compositions of the present invention are cross-linkable. "Crosslinkable" means that the cable layer can be crosslinked before it is used for its end use. The crosslinkable polymer composition comprises a polyolefin (a), an ion exchange additive (c), and an amount of peroxide (b) as defined above or below in the claims. In addition, the crosslinked polymer composition or each crosslinked polyolefin (a) is crosslinked via a radical reaction using the amount of peroxide (b) present in the polymer composition prior to crosslinking. The crosslinked polymer composition has a typical network structure, i.e., inter-polymer crosslinking (crosslinking), as is well known in the art. As is apparent to those skilled in the art, the crosslinked polymer can be defined and defined as a feature present in the polymer composition or polyolefin (a) before or after crosslinking, as referred to herein or as is apparent in the context. For example, the presence and amount of peroxide in the polymer composition or the type and compositional characteristics of the polyolefin component (a), such as MFR, density and / or unsaturation, are defined before crosslinking unless otherwise stated, , E. G., Electrical conductivity, is measured from the crosslinked polymer composition.

The present invention further provides a crosslinked polymer composition comprising a crosslinked polyolefin (a), wherein the polymer composition comprises (a) a polyolefin, (b) a crosslinking agent, Oxide, and (c) an ion exchange additive, wherein the amount of peroxide is preferably less than -00-35 millimoles per kg of polymer composition.

Most preferably, the polymer composition of the present invention comprises peroxide (b). Thus, the present crosslinked polymer composition is preferred and can be obtained by crosslinking using peroxide (b) as defined above or in the amounts defined below.

The present invention relates to a crosslinked polymer composition comprising a crosslinked polyolefin (a) in the presence of an ion exchange additive (c) using peroxide (b) in an amount of less than -00-35 millimoles per kg of polymer composition .

The terms " crosslinkable ", "crosslinked ", and" crosslinked polymer composition ", which can be obtained by crosslinking, are used interchangeably herein and refer to the category of "product by process" It means that it has a technical feature due to the bonding step.

Unit "-O-O-millimoles per kg of polymer composition" means herein the content (millimoles) of peroxide functionality per kg of polymer composition as measured from the polymer composition prior to crosslinking. For example, -O-O- 35 millimoles per kilogram of polymer composition corresponds to 0.95 weight percent of well-known dicumyl peroxide based on the total amount of polymer composition (100 weight percent).

"Crosslinked polymer composition" is also referred to herein simply as "polymer composition ". "Crosslinkable polymer composition" is also referred to herein simply as "polymer composition ". The meaning is clear from the context.

The electrical conductivity is measured according to the DC conductivity method described herein under the heading "Crystallization Method ". The "reduced" or "lower" electrical conductivity used interchangeably herein means that the value obtained from the DC conductivity method is low (i.e., decreased).

The preferred polyolefin (a) is polyethylene produced in a high pressure process (HP). The polyolefin (a) including its preferred ally is described in more detail below or in the claims.

For the ion exchange additive (c) of the polymer composition:

It is also possible to add the ion exchange additive (c) of the polymer composition of the present invention to the additive composition itself, that is to say in pure state, or as an additive composition supplied by the additive producer, And may be added to the polymer composition. In addition, such an ion exchange additive (c) or additive composition thereof may be incorporated into itself, for example, as supplied by an additive producer or in an additional carrier material, such as a polymer carrier such as a so-called master batch (MB) May be added to the polymer composition. The amount of ion exchange additive (c) given below and in the claims is based on the total weight (amount) (100 wt.%) Of the polymer composition itself, i.e. the weight (quantity) of said ion exchange additive (c) to be.

The ion exchange additive (c) of the polymer composition of the present invention is preferably an inorganic ion exchange additive, more preferably an inorganic anion exchange additive. Further, preferably, the anion exchange additive (c) is capable of exchanging anions with a halogen (i.e., a capturing halogen), preferably at least a chlorine-based substance. More preferably, the ion exchange additive (c) has a thin layer structure.

A preferred embodiment of the ion exchange additive (c) is a thin layer anion exchanger, preferably a thin layer anion exchanger comprising an anionic intermediate layer. A preferred layered ion exchange additive (c) comprises a thin layer forming a stable host lattice and an exchangeable anionic intermediate layer between the thin layers. The anionic intermediate layer herein means that the intermediate layer comprises an anion that is weakly bound to the thin layer and can be exchanged with the anionic material present in the polyolefin (a) of the polymer composition. Figure 1 schematically shows a thin layer structure of an anion exchange additive as a preferred ion exchange additive (c). (A schematic partial cross section shows two thin layers and an intermediate layer therebetween). In this exemplary embodiment, the middle layer of the thin-layer anion exchange material (c) is preferably from ₃ CO ² that can be exchanged with the anionic substances present in the polymer composition, such as polyolefin components (a) ^- comprises an anion. In addition, the preferred embodiments, a stable thin layer is preferably e.g. Mg-, Al-, Fe-, Cr-, Cu-, Ni- or Mn- cation or any mixture thereof, more preferably at least Mg ^{2 +} - cationic materials, more preferably Mg ^{2 +} and Al ^{3 +} -cationic materials.

In this preferred embodiment, the most preferred ion exchange additive (c) is a thin layer of anion exchange additives, preferably exchangeable CO ₃ ² of hydrotalcite type ^- for the synthesis of hydrotalcite type, including anionic intermediate layer containing the anion anion exchange thin layer of additives, more preferably the general formula ^{_{Mg x R y (3+) (}} OH) z (CO 3) k * nH 2 O ( ^{here, R (3+) = Al,} Cr or Fe, preferably Al). ≪ / RTI > In the above formula, preferably, x is 4 to 6; y is 2; z is from 6 to 18; k is 1; n is from 3 to 4; It is obvious that the ratio may vary depending on the amount of crystals, for example. As a non-limiting example, only the formula Mg ₆ R ₂ ⁽³⁺⁾ (OH) ₁₆ CO ₃ * 4H ₂ O, where R ⁽³⁺⁾ = Al, Cr or Fe, have.

Also, in this preferred embodiment, the ion exchange additive (c), preferably hydrotalcite, as set forth in the following or the appended claims, may be modified as is well known in the art, for example, .

The ion exchange additive (c) suitable for the present invention is, for example, commercially available. Among the preferred ion exchange additives (c), commercially available synthetic hydrotalcites such as those supplied by Kisuma Chemicals under the trade designation DHT-4V (IUPAC designation: dialkylhexamagnesium carbonate 8 hexadecahydroxide, CAS No. 11097-59-9).

As mentioned above, optional and preferred peroxides (b) are used in an amount of -OO- 2.0 millimoles per kilogram of polymer composition, preferably -00-3.0 millimoles per kilogram of polymer composition, more preferably -OO per mil of polymer composition - < / RTI > 4.0 millimoles or more. More preferably, the preferred crosslinked polymeric compositions of the present invention have a molecular weight of less than -00-34 millimoles per kilogram of polymer composition prior to crosslinking, preferably less than -00-33 millimoles per kilogram of polymer composition, more preferably 1 kilogram More preferably from -0.0 to 10.0 to 30 millimoles per kg of polymer composition, even more preferably from about 5.0 to about 30 millimoles per kg of polymer composition, more preferably from -0.0 to 7.0 to 30 millimoles per kg of polymer composition, (B) in an amount of 15 to 30 millimoles of OO. The content of peroxide (b) depends on the desired level of crosslinking, and in one embodiment the peroxide (b) content before crosslinking is more preferably -OO- 17 to 29 millimoles per kg of polymer composition do. In addition, the polyolefin (a) may be unsaturated, in which case the peroxide (b) content may vary depending on the degree of unsaturation

More preferably, the crosslinked polymer composition of the present invention has a viscosity of less than < 0.01 when measured according to the DC conductivity method described under the heading "Crystallization Method" after crosslinking (lower values are not detected by DC conductivity measurements) More preferably from 0.01 to 80 fS / m, more preferably from 0.01 to 80 fS / m, further preferably from 0.01 to 70 fS / m, further preferably from 0.01 to 60 fS / m, M, more preferably from 0.01 to 15 fS / m, and most preferably from 0.05 to 10 fS / m, more preferably from 0.01 to 20 fS / m, m, even more preferably between 1.0 and 10 fS / m.

In addition, the electrical conductivity of the polymer composition is surprisingly good with respect to the electrical conductivity of the undegraded polymer composition crosslinked with a conventional amount of peroxide without removing volatile by-products after cross-linking, i.e., without degassing. Thus, if desired, the degassing step of the crosslinked cable containing the polymer composition can be significantly shortened and / or can be accomplished under less demanding conditions during the cable manufacturing process, which of course improves production efficiency. Thus, the degassing step during cable fabrication can be shortened if desired.

Also unexpectedly, the peroxide (b) content can be reduced without sacrificing the mechanical properties of the resultant crosslinked polymer composition, which is important for the power cable layer. Therefore, unexpectedly, in addition to the reduced electrical conductivity of the polymer composition, one or more of the mechanical properties selected from the PENT (Pennsylvania Notch Test), more preferably all of the tensile properties expressed as stress at break and fracture strain One or both of which remain adequately maintained or at least about the same level as the mechanical properties of the prior art crosslinked polymer compositions used in the cable layer. The reason for the favorable balance between improved electrical conductivity and good mechanical properties has not been fully elucidated. Without wishing to be bound by any theory, one of the reasons may be that an unexpectedly high degree of crystallinity (%) of the crosslinked polymer is maintained relative to the degree of crystallinity obtained using the usual concentration of peroxide. Thus, and preferably also, the polymer compositions of the present invention have an unexpected balance between electrical and mechanical properties, which is very advantageous, for example, with DC power cables, and surprisingly HV or EHV DC power cables.

Thus, the preferred crosslinked polymeric compositions of the present invention have a molecular weight of greater than or equal to 200 hours, preferably greater than or equal to 400 hours, as measured according to the PENT test under a load of 2 MPa at an aging temperature of 70 DEG C as described under the heading ≪ RTI ID = 0.0 > PENT < / RTI > PENT shows resistance to slow crack propagation, and the larger the value, the better the resistance.

More preferably, the preferred crosslinked polymer compositions of the present invention are those which, when measured according to the tensile test method according to ISO 527-2: 1993 using sample geometry 5A, And exhibits advantageous tensile properties expressed by strain upon fracture.

Thus, the crosslinked polymer compositions of the present invention are used to determine the electrical properties and their desirable mechanical properties. The preparation of individual samples of the crosslinked polymer composition is hereinafter described under the heading "Crystallization Method ".

In addition, the electrical DC conductivity is very low, even if the content of the preferred peroxide (b) is very low, as defined below or in the claims, and surprisingly it can maintain very good mechanical properties required for wire and cable applications.

The low electrical conductivity of the polymer composition is very favorable for power cables and, because of its low electrical DC conductivity, is a direct current (DC) power cable, preferably low voltage (LV), medium voltage (MV), high voltage (HV) Cable, and is more preferable for a DC power cable operating at any voltage, such as an HV DC cable, preferably at a voltage higher than 36 kV.

The present invention further provides a cable, preferably a power cable, more preferably a direct current (DC) power cable, comprising a conductor surrounded by one or more layers, wherein at least one of the layer (s) (B) optionally and preferably, a peroxide which is preferably present and more preferably present in an amount of from less than -00 to 35 mmol per kg of the polymer composition, and (c) an ion exchange additive, And preferably comprises a polymer composition as defined below or in the claims. Preferably, at least one layer of the cable is an insulating layer.

More preferably, the present invention relates to a power cable, preferably a direct current (DC) power cable, more preferably an HV or EHV DC power source, comprising at least an inner semiconductor layer, an insulating layer, Wherein at least one layer, preferably an insulating layer, is formed from a mixture of (a) a polyolefin, (b) optionally and preferably also preferably, and more preferably from -00 to 35 millimoles per kilogram of polymer composition , And (c) an ion exchange additive. The polymer composition of the present invention is preferably composed of this composition.

It is preferred that the cable of the present invention is cross-linked. The present invention is also directed to a crosslinked power cable, preferably a crosslinked direct current (DC) power cable comprising a conductor surrounded by one or more layers, wherein at least one of the layer (s) (A) and an ion exchange additive (c) crosslinked (i.e., obtained by cross-linking) with an amount of peroxide (b) of less than -OO- 35 millimoles And is preferably composed of this composition. More preferably, the present invention relates to a method of manufacturing a cross-linked power cable, preferably a cross-linked direct current (DC) power cable, comprising at least an inner semiconductor layer, an insulating layer and a conductor surrounded by the outer semiconductor layer, (A) a polyolefin, (b) an amount of less than -00-35 millimoles per kilogram of polymer composition, of crosslinked HV or EHV DC power cable, wherein at least one layer, preferably an insulating layer, And (c) an ion exchange additive, wherein the polyolefin (a) is crosslinked in the presence of the (b) peroxide.

The present invention also relates to a method of reducing the electrical conductivity of an optionally and preferably crosslinked polymer composition comprising optionally and also preferably crosslinked polyolefins using peroxide, i.e. a process for providing a low electrical conductivity (A) polyolefin, (b) optionally and preferably, if present, less than -00-35 millimoles per kg of polymer composition, preferably less than -00-34 millimoles per kilogram of polymer composition, Per kg of polymer composition, preferably less than -00 to 30 millimoles per kg of polymer composition, preferably less than -0.00 to 30 millimoles per kilogram of polymer composition, more preferably from -0.0 to 5.0 to 30 millimoles per kilogram of polymer composition, 7.0 to 30 millimoles of OO, more preferably in an amount of from -0.0 to 10.0 to 30 millimoles per kg of polymer composition, Peroxide, and (c) an ion exchange additive together to form a polymer composition as defined in the preceding claim; And, optionally and preferably, crosslinking the polyolefin (a) in the presence of the peroxide (b).

More preferably, the present invention relates to a process for the production of a polyolefin (a), optionally at least an insulating layer, preferably at least an inner semiconductor layer, an insulating layer and an outer semiconductor layer, Optionally and preferably also cross-linked direct current (DC) power cables, preferably arbitrarily and preferably also cross-linked HV or < RTI ID = 0.0 > A method for reducing the electrical conductivity of an optionally and preferably crosslinked polymer composition of an EHV DC power cable, wherein at least the insulating layer comprises (a) a polyolefin, (b) optionally and preferably, And more preferably present in an amount of less than -OO- 35 millimoles per kg of polymer composition Includes a polymer composition that is a peroxide, and (c) to the above, including the ion exchange, or additives as defined in the claims.

The present invention also relates to the production of a cable, preferably a power cable, more preferably a crosslinkable and crosslinkable power cable, preferably a crosslinkable and crosslinked direct current (DC) power cable, as defined above or below .

(B) optionally, a peroxide, if present, which is preferably present in an amount of less than -00-35 millimoles per kilogram of polymer composition, and (c) a polyolefin, The present invention further provides an ally of the polymer composition as defined in the following or the claims, including ion exchange additives.

A method for reducing electrical conductivity, a method for reducing electrical conductivity, a method for reducing electrical conductivity, a method for reducing electrical conductivity, a polymeric composition including a non-crosslinked polymer composition and a crosslinked polymer composition, or other desirable members of the above- The invention applies equally independently to cables, preferably cross-linked and cross-linked DC power cables, and power cables, preferably the method of making the cross-linked and cross-linked DC power cables of the present invention.

(a) Polyolefin  ingredient

The following preferred embodiments, properties and alliances of the polyolefin component (a) suitable for the polymer composition are generalized, and they can be used in any order or together to further define the preferred embodiment of the polymer composition. It is also apparent that the content of the given substrate is applied arbitrarily and preferably to the polyolefin (a) before crosslinking.

The term polyolefin (a) refers to both olefin homopolymers and copolymers of olefins and one or more comonomer (s). As is well known, "comonomer" refers to a copolymerizable comonomer unit.

 The polyolefin (a) may be any polyolefin, such as a conventional polyolefin, which is suitable as a polymer of an electrical cable, preferably a layer of a power cable, preferably an insulating layer.

The polyolefin may be, for example, a commercially available polymer or may be prepared according to or analogously to known polymerization processes as described in the chemical literature.

More preferably, the polyolefin (a) is a polyethylene produced in a high pressure process (HP), more preferably a low density polyethylene LDPE produced in a high pressure process. The meaning of LDPE polymers is well known and documented in the literature. Although the term LDPE is abbreviation for low density polyethylene, it is understood that the term encompasses LDPE-like HP polyethylenes of low density, medium density and high density, rather than limiting the density range. The term LDPE describes and distinguishes only the properties of HP polyethylene with typical characteristics such as different branching structures as compared to PE produced in the presence of an olefin polymerization catalyst.

The LDPE as the polyolefin (a) may be a low density homopolymer of ethylene (referred to herein as an LDPE homopolymer) or a low density copolymer of ethylene and one or more comonomer (s) (referred to herein as an LDPE copolymer). The at least one comonomer of the LDPE copolymer is preferably selected from the group consisting of the polar comonomer (s), the non-polar comonomer (s) or the polar comonomer (s) and the non-polar comonomer (s) ≪ / RTI > In addition, the LDPE homopolymer or LDPE copolymer as the polyolefin (a) may be optionally unsaturated.

(S), carbonyl group (s), carboxyl group (s), ether group (s), or ester group (s) as the polar comonomer of the LDPE copolymer as the polyolefin (a) ) Or a mixture thereof may be used. More preferably, the comonomer (s) containing the carboxyl group (s) and / or ester group (s) is used as the polar comonomer. Even more preferably, the polar comonomer (s) of the LDPE copolymer is selected from the group of acrylate (s), methacrylate (s) or acetate (s) or any mixture thereof. When present in the LDPE copolymer, the polar comonomer (s) is preferably selected from the group of alkyl acrylates, alkyl methacrylates or vinyl acetates or mixtures thereof. More preferably, the polar comonomer is selected from C ₁ - to C ₆ -alkyl acrylates, C ₁ - to C ₆ -alkyl methacrylates or vinyl acetate. Even more preferably, the polar LDPE copolymer is a copolymer of ethylene with C ₁ - to C ₄ -alkyl acrylates such as methyl, ethyl, propyl or butyl acrylate, or vinyl acetate, or any mixture thereof.

As the non-polar comonomer (s) of the LDPE copolymer as the polyolefin (a), comonomer (s) other than the polar comonomer defined above may be used. Preferably, the non-polar comonomer is selected from the group consisting of a hydroxyl group (s), an alkoxy group (s), a carbonyl group (s), a carboxyl group (s), an ether group (s) Other than the monomer (s). One group of preferred non-polar comonomers (s) is a monounsaturated (= one double bond) comonomer (s), preferably an olefin, preferably an alpha-olefin, more preferably a C ₃ to C ₁₀ Alpha-olefins such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, styrene, 1-octene, 1-nonene; Polyunsaturated (= more than one double bond) comonomer (s); Silylene-containing comonomer (s); Or any mixture thereof, and preferably consists of these. The polyunsaturated comonomer (s) are described further below in the context of unsaturated LDPE copolymers.

When the polyolefin (a) is an LDPE polymer that is a copolymer, it preferably contains 0.001 to 50 wt%, more preferably 0.05 to 40 wt%, even more preferably less than 35 wt% of one or more comonomer (s) By weight, preferably less than 30% by weight, more preferably less than 25% by weight.

The polymer composition, preferably its polyolefin (a) component, more preferably the LDPE polymer, may optionally be unsaturated. That is, the polymer composition, preferably the polyolefin (a), preferably the LDPE polymer, may comprise a carbon-carbon double bond. As used herein, "unsaturated" means that the polymer composition, preferably the polyolefin, contains carbon-carbon double bonds per 1000 carbon atoms in a total amount of at least 0.4 per 1000 carbon atoms.

As is well known in the art, unsaturation is provided to the polymer composition by low molecular weight (Mw) compounds such as polyolefin (a), crosslinking propellant (s) or scorch retarding additive . The total amount of double bonds means double bonds determined from known sources (s) that are deliberately added here to contribute to unsaturation. When two or more of the above sources of double bonds are selected to provide unsaturation, the total amount of double bonds in the polymer composition means the sum of the double bonds present in the double bond source. It is clear that it enables quantitative infrared (FTIR) determination using characteristic model compounds for tailoring for each selected source.

Any double bond measurements are made prior to crosslinking.

When the polymer composition is unsaturated before crosslinking, it is preferred that the unsaturation derives from at least the unsaturated polyolefin (a) component. More preferably, the unsaturated polyolefin (a) is an unsaturated polyethylene (a), more preferably an unsaturated LDPE polymer, even more preferably an unsaturated LDPE homopolymer or an unsaturated LDPE copolymer. When the polyunsaturated comonomer (s) are present in the LDPE polymer as the unsaturated polyolefin (a), the LDPE polymer is an unsaturated LDPE copolymer.

In a preferred embodiment, the term "total amount of carbon-carbon double bonds" is defined from unsaturated polyolefin (a) and, if not otherwise specified, represents a double bond derived from a vinyl group, a vinylidene group and a trans- It refers to the combined amount. Of course, the polyolefin (a) does not necessarily contain all three types of double bonds. However, any of the three types, if any, is calculated as "total amount of carbon-carbon double bonds ". The amount of each type of double bond is measured as indicated under the heading "Crystallization Method ".

When the LDPE homopolymer as the polyolefin (a) is unsaturated, the unsaturation may be provided by a chain transfer agent (CTA) such as, for example, propylene and / or by polymerization conditions. When the LDPE copolymer is unsaturated, the unsaturation may be provided by one or more of the following means: by chain transfer agent (CTA), by one or more polyunsaturated comonomer (s) or by polymerization conditions. It is well known that selected polymerization conditions such as peak temperature and pressure can have an effect on the degree of unsaturation. In the case of unsaturated LDPE copolymers, it is preferably combined with other comonomer (s) such as polar comonomer (s) preferably selected from one or more polyunsaturated comonomers and optionally acrylate or acetate comonomer (s) and ethylene Unsaturated LDPE < / RTI > More preferably, the unsaturated LDPE copolymer is at least an unsaturated LDPE copolymer of polyunsaturated comonomer (s) and ethylene.

The polyunsaturated comonomer suitable for the unsaturated polyolefin (a) preferably consists of a carbon straight chain having at least 4 carbon atoms between at least 8 carbon atoms and a non-conjugated double bond (at least one of which is the terminal) , Said polyunsaturated comonomer comprises a diene, preferably at least 8 carbon atoms, a first carbon-carbon double bond at the terminal and a second carbon-carbon double bond that is non-conjugated to the first double bond It is Daien. Preferred dienes are selected from C ₈ to C ₁₄ non-conjugated dienes or mixtures thereof, more preferably selected from 1,7-octadienes, 1,9-decadienes, 1,11-dodecadienes , 1,13-tetradecadienes, 7-methyl-1,6-octadienes, 9-methyl-1,8-decadiene or mixtures thereof. Even more preferably, the diene is selected from 1,7-octadiene, 1,9-decadienes, 1,11-dodecadienes, 1,13-tetradecadienes or any mixture thereof , But is not limited to the above dienes.

It is well known that propylene can contribute, for example, to the total amount of C-C double bonds, preferably to the total amount of vinyl groups, by using propylene as the comonomer or as chain transfer agent (CTA) or both. In the present application, when a compound which may also function as a comonomer, such as propylene, is used as the CTA to provide a double bond, the comonomer comonomer is not calculated to the comonomer content.

When the polyolefin (a), and more preferably the LDPE polymer, is unsaturated, it is preferably present in an amount greater than 0.5 carbon-carbon double bonds per 1000 carbon atoms, which, if present, are derived from vinyl, vinylidene and trans- Lt; / RTI > The upper limit of the amount of the carbon-carbon double bond present in the polyolefin is not limited, and may be preferably less than 5.0 per 1000 carbon atoms, preferably less than 3.0 per 1000 carbon atoms.

For example, in some embodiments where a higher degree of crosslinking is required with a lower peroxide content, the total amount of carbon-carbon double bonds derived from vinyl, vinylidene and trans-vinylene groups, when present in the unsaturated LDPE, More than 0.50 per 1000 carbon atoms, preferably more than 0.60 per 1000 carbon atoms. This larger amount of double bonds is desirable, for example, where high cable production speeds are required and / or when it is necessary to minimize or avoid deflection problems that may arise, for example, in accordance with the desired end use and / or cable manufacturing process . The higher double bond content in combination with the "lower" peroxide content of the present invention is also desirable in cable applications (e.g., DC power cables) where very severe mechanical properties and / Do.

More preferably, the polyolefin (a) is unsaturated and contains at least vinyl groups, the total amount of vinyl groups being preferably greater than 0.05 per 1000 carbon atoms, even more preferably greater than 0.08 per 1000 carbon atoms, Preferably greater than 0.11 per 1000 carbon atoms. Preferably, the total amount of vinyl groups is 4.0 or less per 1000 carbon atoms. More preferably, the polyolefin (a) before cross-linking is greater than 0.20 per 1000 carbon atoms, more preferably greater than 0.30 per 1000 carbon atoms, and most preferably greater than 0.40 per 1000 carbon atoms, Lt; / RTI > In some demanding embodiments, preferably power cables, more preferably DC power cables, one or more layers, preferably an LDPE polymer containing vinyl groups in a total amount greater than 0.50 per 1000 carbon atoms, preferably an insulating layer, LDPE < / RTI >

Unexpectedly, unsaturation additionally contributes to the above desirable balance of low conductivity and mechanical properties. The preferred polyolefin (a) for use in the polymer composition is an unsaturated LDPE copolymer of a polyunsaturated comonomer, preferably a diene as defined above, and optionally another comonomer (s). Also preferably, such unsaturated LDPE copolymers of ethylene with one or more polyunsaturated comonomers, preferably the dienes defined above and optionally other comonomers, contain vinyl groups. In this embodiment, the total amount of vinyl groups is preferably as defined above, below or in the claims. The unsaturated LDPE copolymer is very useful in a method of further reducing the electrical conductivity of a crosslinked polymer composition, preferably an insulating layer of a power cable, preferably a DC power cable.

Typically and preferably, the density of the polyolefin (a), preferably the LDPE polymer, is higher than 860 kg / m ^{3 for} wire and cable (W & C) applications. Preferably, the polyolefin (a), preferably the density of the LDPE polymer, an ethylene homopolymer or copolymer is 960kg / m ³ or less, preferably from 900 to 945kg / m ^3. The MFR ₂ (2.16 kg, 190 캜) of the polyolefin (a), preferably the LDPE polymer is preferably 0.01 to 50 g / 10 min, more preferably 0.1 to 20 g / 10 min, and most preferably 0.2 to 10 g / 10 minutes.

Thus, the polyolefin (a) of the present invention is preferably produced at high pressure by free radical initiated polymerization (referred to as high pressure (HP) radical polymerization). The HP reactor may be, for example, a well known tubular reactor or autoclave reactor or a mixture thereof, preferably a tubular reactor. The preferred polyolefin (a) is also optionally and preferably an unsaturated LDPE homopolymer or an unsaturated LDPE copolymer of ethylene with one or more comonomer (s) as defined above. The LDPE polymers obtainable by the process of the present invention preferably provide advantageous electrical properties as defined above or below. Adjustment of process conditions to further control other properties of the polyolefin (a) according to high pressure (HP) polymerization and the desired end use is well known and described in the literature and can be readily utilized by those skilled in the art . A suitable polymerization temperature is 400 占 폚 or less, preferably 80 to 350 占 폚, and the pressure is 70 MPa or more, preferably 100 to 400 MPa, more preferably 100 to 350 MPa. The pressure can be measured at least after the compression step and / or after the tubular reactor. The temperature can be measured at several points during all stages.

The polymer obtained after separation is typically in the form of a polymer melt, which is mixed and pelletized in a pelletizing zone, such as a pelletizing extruder, which is typically placed in connection with an HP reactor system. Optionally, the additive (s), such as antioxidant (s), can be added to the mixer in a known manner to produce a polymer composition.

Further details of the production of ethylene (co) polymers by high pressure radical polymerization can be found in Encyclopedia of Polymer Science and Engineering, Vol. 6 (1986), pp 383-410; And Encyclopedia of Materials: Science and Technology, 2001 Elsevier Science Ltd .: "Polyethylene: High-pressure, R. Klimesch, D. Littmann and F.-O. Mahling, -7184].

In the case of preparing unsaturated LDPE copolymers of ethylene, as is well known, depending on the properties required of the unsaturated LDPE copolymer and the amount of CC double bonds, for example, one or more polyunsaturated comonomer (s) By polymerizing ethylene using the desired feed ratio of monomers, preferably ethylene and polyunsaturated comonomers and / or chain transfer agents, in the presence of a catalyst, a transfer agent (s), process conditions, or any combination thereof, The double bond content can be adjusted. WO 9308222 describes high pressure radical polymerization of polyunsaturated monomers with ethylene. As a result, unsaturation can be uniformly distributed along the polymer chains in a random copolymerization manner. Also, for example, WO 9635732 describes high pressure radical polymerization of ethylene and certain types of polyunsaturated?,? - divinylsiloxanes.

Polymer composition

The polymer compositions of the present invention typically comprise at least 50 wt%, preferably at least 60 wt%, more preferably at least 70 wt%, based on the total weight of polymeric component (s) present in the polymer composition, (A) of at least 75% by weight, more preferably 80 to 100% by weight, and still more preferably 85 to 100% by weight. The preferred polymer composition consists of the polyolefin (a) as the only polymer component. This expression means that the polymer composition contains no additional polymer components and contains the polyolefin (a) as the only polymer component (s). However, it is to be understood that in the present application the polyolefin (a), optionally and preferred peroxides (b), and optionally other additives, such as a mixture with the carrier polymer as the ion exchange additive (c) It should be understood that other components than the ion exchange additive (c) may be included.

The amount of ion exchange additive (c), preferably hydrotalcite, as defined in the foregoing or the following claims is usually dependent on the desired end use (for example, the desired conductivity level) . Preferably, the polymer composition comprises itself, i. E. Less than 1% by weight, based on the total weight of the polymer composition, of the ion exchange additive (c), preferably hydrotalcite, as defined in the following, By weight, preferably less than 0.8% by weight, preferably 0.000001 to 0.7% by weight, preferably 0.000005 to 0.6% by weight, more preferably 0.000005 to 0.5% by weight, more preferably 0.00001 to 0.1% Is preferably 0.00001 to 0.08% by weight, more preferably 0.00005 to 0.07% by weight, still more preferably 0.0001 to 0.065% by weight, still more preferably 0.0001 to 0.06% by weight, still more preferably 0.0001 to 0.05% by weight, Is 0.0001 to 0.045% by weight, more preferably 0.00015 to 0.035% by weight, still more preferably 0.0002 to 0.025% by weight, still more preferably 0.0003 to 0.015% by weight By weight, more preferably 0.0005 to 0.01% by weight, still more preferably 0.0008 to 0.005% by weight, still more preferably 0.001 to 0.004% by weight, and still more preferably 0.0015 to 0.0035% by weight.

The amount of optional and preferred peroxide (b) is as defined above or in the claims. Prior to optional and preferred crosslinking, the polymer compositions of the present invention comprise at least one peroxide (b) containing at least one -O-O- linkage. Of course, when two or more different peroxide products are used in the polymer composition, the amount (millimoles) of -OO- per kg of polymer composition as defined in the following, or the following claims, per kg of polymer composition of each peroxide product- OO-. Examples of suitable organic peroxides (b) include di-tert-amyl peroxide, 2,5-di (tert-butylperoxy) -2,5-dimethyl- Di (tertiary-butyl) peroxide, dicumyl peroxide, butyl-4,4-bis (tertiary- butylperoxy) -2,5-dimethylhexane, tert- (Tert-butylperoxy) -valerate, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, tertiary-butylperoxybenzoate, dibenzoyl peroxide , Bis (tert-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,6-di (benzoylperoxy) hexane, 1,1-di (tert-butylperoxy) , 1,1-di (tert-amylperoxy) cyclohexane, or any mixture thereof. Preferably, the peroxide is selected from the group consisting of 2,5-di (tert-butylperoxy) -2,5-dimethylhexane, di (tert-butylperoxyisopropyl) benzene, (Tert-butyl) peroxide, or mixtures thereof. Most preferably, peroxide (b) is diqucumperoxide.

In addition, optionally prior to crosslinking, the polymer composition of the present invention may further comprise polymer component (s) and / or additive (s) in addition to polyolefin (a), optional and preferred peroxide (b) and ion exchange additive (S), blowing retarder (s), crosslinking propellant (s), stabilizer (s), processing aid (s), flame retardant additive (s) May contain additional component (s) such as water tree delay additive (s), additive (s) such as additional acid or ion scavenger (s), inorganic filler (s) and voltage stabilizer . The polymer composition preferably contains the additive (s) conventionally used in W & C applications, such as one or more antioxidant (s) and optionally one or more spent retarder (s), preferably one or more antioxidant . The amount of the additive to be used is conventional, and is well known to those skilled in the art, for example, as described above under "Detailed Description of the Invention ".

The polymer composition preferably comprises a polyolefin (a), preferably a polyethylene as the sole polymer component, more preferably optionally and preferably also an LDPE homopolymer or copolymer which can be unsaturated prior to crosslinking.

The end use and end use of the present invention

The novel polymer compositions of the present invention are very useful for a very broad end use of polymers. A preferred use of the polymer composition is for W & C applications, more preferably for one of the power cables, including its preferred alliance, which may be combined in any order with the preferred alliances and properties of the polymer composition and its components as defined in the following, Or more.

A power cable is defined as an energy transfer cable that is operated at any voltage. The polymer compositions of the present invention are well suited for power cables operating at voltages higher than 36 kV, which include high voltage (HV) power cables and high voltage (EHV) power cables, and EHV cables are well known in the art As shown in Fig. The term has a well-known meaning and thus represents the level of operation of such a cable. For HV and EHV DC power cables, the operating voltage is defined here as the voltage between the ground and the conductors of the high voltage cable. Typically, HV DC power cables and EHV DC power cables operate at voltages above 40 kV, and even above 50 kV. Power cables operating at very high voltages (actually, but not exclusively, as high as 900 kV) are known in the art as EHV DC power cables.

The polymer composition may be used as a layer material of a DC power cable operated at a voltage higher than 36 kV, such as a power cable, preferably a direct current (DC) power cable, more preferably a well known HV or EHV DC power cable .

Preferably a power cable, more preferably a cable comprising a conductor surrounded by at least one layer, preferably at least an insulating layer, more preferably at least an inner semiconductor layer, an insulating layer and an outer semiconductor layer, A power cable, preferably a crosslinkable DC power cable, is provided, wherein one or more of the layer (s), preferably the insulating layer, is made of (a) polyethylene preferably produced in a high pressure process, more preferably an unsaturated LDPE (B) optionally and preferably is preferably present and more preferably less than -00-35 millimoles per kg of polymer composition, preferably less than -00-34 millimoles per kilogram of polymer composition, -OO- 33 millimoles or less per kg of the polymer composition, more preferably-5.0 to 30 millimoles per kg of the polymer composition, Preferably in an amount of from -0.0 to 7.0 to 30 millimoles per kg of polymer composition, more preferably from -0.0 to 10.0 to 30 millimoles per kg of polymer composition, even more preferably from -0.005 to 30 millimoles per kg of polymer composition And (c) an ion exchange additive. The composition of the present invention preferably comprises the composition. Depending on the desired degree of crosslinking and the degree of unsaturation of the polymer composition, preferably the polyolefin (a), in some cases the peroxide (b) content of the polymer composition is more preferably -OO- 17 to 29 mmol per kg of polymer composition have.

The term "conductor" means that the conductors in the above and herein below include one or more wires. The cable may also include one or more such conductors. Preferably, the conductor is an electrical conductor and comprises at least one metal wire.

As is well known, the cables optionally surround additional layers such as screen (s), jacket layer, other protective layer (s), or any combination thereof, such as an insulating layer or, if present, May comprise a layer.

The present invention also relates to a process for preparing a polymer composition which comprises (a) providing a polymer composition and mixing, preferably melt mixing, in an extruder, (b) Adding at least one layer, preferably at least an insulating layer, by applying a molten mixture, and (c) optionally and preferably, at least crosslinking the polymer layer of the at least one layer, preferably the insulating layer, Wherein the at least one layer, preferably the insulating layer, comprises at least one of (a) a polyolefin, (b) optionally and preferably also a peroxide, and (c) an ion exchange additive , And preferably comprises the composition, more preferably the amount of the peroxide Is preferably -OO- 34 millimoles or less per kg of the polymer composition, preferably less than -00-35 millimoles per 1 kg of the polymer composition, preferably -OO- 30 millimoles or less per kg of the polymer composition, More preferably from -0.0 to 7.0 to 30 millimoles per kg of polymer composition, more preferably from -0.0 to 10.0 to 30 millimoles per kilogram of polymer composition, more preferably from-5.0 to 30 millimoles per kilogram of polymer composition, to be.

A preferred method is for producing a power cable, preferably a DC power cable, more preferably an HV DC power cable, comprising a conductor surrounded by an inner semiconductor layer, an insulating layer and an outer semiconductor layer in that order, a) providing a first semiconductor composition for an inner semiconductor layer comprising a polymer, carbon black and optionally other component (s), mixing, preferably melt mixing, in an extruder, providing an insulating composition for the insulating layer, Preferably melt mixing, and providing a second semiconductor composition for an external semiconductor layer comprising a polymer, carbon black and optionally other component (s), and mixing, preferably melt mixing, in an extruder; (b) applying a molten mixture of the first semiconductor composition obtained in step (a) on the conductor, preferably by co-extrusion, to form an inner semiconductor layer, and adding a molten mixture of the insulating composition obtained in step (a) To form an insulating layer, and adding a molten mixture of the second semiconductor composition obtained in step (a) to form an external semiconductor layer; And (c) optionally and preferably, at least one of the insulating composition of the insulating layer of the obtained cable, the first semiconductor composition of the inner semiconductor layer and the second semiconductor composition of the outer semiconductor layer, And more preferably an insulating composition of an insulating layer, a first semiconductor composition of an inner semiconductor layer, and a second semiconductor composition of an outer semiconductor layer under crosslinking conditions, wherein at least the insulating composition comprises ( The composition preferably comprises, and preferably consists of, a polymer composition as defined in the following or claimed claims, comprising a) a polyolefin, b) optionally and also preferably a peroxide, and c) , More preferably the amount of peroxide is less than -00-35 millimoles per kilogram of polymer composition, preferably per kilogram of polymer composition - OO-34 millimoles or less, preferably about -00 to about 33 millimoles per kg of polymer composition, preferably about -0.00 to about 30 millimoles per kilogram of polymer composition, more preferably about-5.0 to about 30 millimoles per kg of polymer, Preferably from -0.0 to 7.0 to 30 millimoles per kg of the polymer composition, more preferably from -0.0 to 10.0 to 30 millimoles per kg of the polymer composition.

The polymers of the first semiconductor composition and the second semiconductor composition are preferably selected from the group consisting of polyolefins produced in the presence of an olefin polymerization catalyst (also known as low-pressure polyolefins, preferably low-pressure polyethylenes) Is the polyolefin (a) described. The carbon black may be any conventional carbon black used in a semiconductor layer of a DC power cable, preferably a semiconductor layer of a DC power cable. Preferably, the carbon black has at least one of the following properties: a) a primary particle size of at least 5 nm, defined as the number average particle size according to ASTM D3849-95a, Dispersion Procedure D, b) at least 30 mg / g according to ASTM D1510 Iodine, c) an oil absorption of at least 30 ml / 100 g, measured in accordance with ASTM D2414. Non-limiting examples of carbon black are, for example, acetylene carbon black, furnace carbon black and Ketjen carbon black, preferably furnace carbon black and acetylene carbon black. Preferably, the first and second semiconductor polymer compositions comprise from 10 to 50% by weight of carbon black, based on the weight of the semiconductor composition.

The melt mixing means mixing at a temperature higher than the melting point of at least the main polymer component (s) of the resulting mixture and is typically carried out at a temperature 10 to 15 ° C or more higher than the melting or softening point of the polymer component (s) .

The term "(co) extrusion" is used herein to refer to the extrusion of two or more layers, as is well known in the art, or two or more of the layers may be coextruded in the same extrusion step . The term "(co) extrusion" is also used herein to refer to the simultaneous formation of all or a portion of the layer (s) using one or more extrusion heads.

As is well known, the polymer compositions of the present invention and optional and preferred first and second semiconductor compositions can be fabricated before or during the cable fabrication process. In addition, the polymer compositions of the present invention and optional and preferred first and second semiconductor compositions can each independently include some or all of its component (s) prior to introduction into the (melt) mixing step a) of the cable manufacturing process have.

Preferably, the polymer composition of the present invention and optionally any of the first and second semiconductor compositions are provided in a cable manufacturing process in the form of a powder, grain or pellet. By pellet is meant herein any polymer product which is usually made by making the polymer (obtained directly from the reactor) prepared in the reactor by post-reactor reforming into solid polymer particles. A well-known post-reactor reforming is to pelletize the molten mixture of polymer product and optional additive (s) in a pelletizing plant into solid pellets. The pellets may have any size and shape.

The mixing step (a) of the polymer composition of the present invention and the preferred first and second semiconductor compositions provided is preferably carried out in a cable extruder. Step a) of the cable manufacturing process may optionally comprise a separate mixing step in the mixer which is connected to and arranged in front of the cable extruder of the cable production line, for example. Mixing in a separate separate mixer can be performed with or without external heating of the component (s) (heating using external heat sources). (S) such as peroxide (s) (b) or ion exchange additive (c), or further additive (s) of the polymer composition of the present invention and optional and preferred first and second semiconductor compositions, If all are added to the polyolefin during the cable manufacturing process, it can be added at any stage during the mixing step (a), for example in an optional separate mixer preceding the cable extruder or at any point (s) of the cable extruder (S) may be performed. The peroxide and optional additive (s) may be added simultaneously or separately, preferably in liquid form, or in a well known master batch, at any stage during the mixing step (a).

In a second embodiment, pre-prepared pellets of a polymer composition comprising optional and preferred peroxide (b) and polyolefin (a) combined with an ion exchange additive (c) are provided in step (a) of the process. In this embodiment, at least an ion exchange additive (c) and optionally an optional and preferred peroxide (b) in its (pure) or mastermass (MB) is added to the polyolefin (a) , Pelletizing the obtained molten mixture into solid pellets, and then providing the solid pellets to step (a) of the cable manufacturing process. However, in this embodiment, the optional and preferred peroxide (b) is preferably impregnated into the formed pellets comprising the polyolefin (a) and the ion exchange additive (c). The optional addition of the additive (s) to the polyolefin (a) can be carried out as described above for the ion exchange additive (c) or optional and preferred peroxide (b).

The polymer composition is most preferably provided in the cable manufacturing process according to the second embodiment.

In a preferred embodiment of the cable manufacturing process, a crosslinkable power cable, preferably a crosslinkable DC power cable, more preferably a crosslinkable HV DC power cable, is produced, wherein the insulation layer is a crosslinkable polyolefin ( (a), optionally and preferably an unsaturated LDPE homopolymer or copolymer, the peroxides (b) and the ion exchange additives (c) in the amounts given above or in the amounts given below, The crosslinkable polyolefin (a) in the insulating layer of the cable is crosslinked under crosslinking conditions in step c). More preferably, in this embodiment, an inner semiconductor layer comprising a first semiconductor composition and preferably composed of a first semiconductor composition, and a polymer composition of the present invention as defined in the following or the claims, Comprising a conductor surrounded by an insulating layer composed of the polymer composition of the present invention as defined above and optionally also an outer semiconductor layer comprising a second semiconductor composition and preferably comprised of a second semiconductor composition, To produce a cable, preferably a cross-linked DC power cable, more preferably a cross-linked HV DC power cable, comprising at least the polymer composition of the insulating layer, optionally and preferably also the first and / One or more, and preferably both, of the second semiconductor composition may be used in step (c) Lt; / RTI > (S) in the presence of an amount of peroxide (b) as defined in the above or the following claims, preferably in the presence of a crosslinking agent (s), preferably in the presence of a free radical generator (Which is preferably the peroxide (s)) of the first semiconductor composition of the inner semiconductor layer.

Thus, the polymer composition of the insulating layer of the present invention is most preferably crosslinked in the presence of the "minor amount" of the peroxide (b) of the present invention as defined in the foregoing or the following claims.

The crosslinking agent (s) may already be present in the optional first and second semiconductor compositions prior to introduction into the crosslinking step c), or may be introduced during the crosslinking step. The peroxide is a preferred crosslinking agent for the optional first and second semiconductor compositions and is preferably included in the pellets of the semiconductor composition before the composition is used in the cable manufacturing process described above.

Crosslinking can be carried out at an elevated temperature, which is selected according to the type of crosslinking agent, as is well known. For example, temperatures higher than 150 DEG C, for example 160 to 350 DEG C, are typical, but are not limited to these.

Processing temperatures and devices are well known in the art, and extruders such as conventional mixers and single or twin screw extruders are suitable for the process of the present invention.

The invention relates to a crosslinked power cable comprising at least one layer, preferably at least an insulating layer, more preferably at least an inner semiconductor layer, an insulating layer and a conductor surrounded by the outer semiconductor layer in that order, DC power cable, preferably a crosslinked HV or EHV DC power cable, wherein at least the insulating layer comprises any of its preferred associates or embodiments defined in the above or the claims, Bonded polymer compositions. Optionally and preferably also, one or both, preferably both, of the inner semiconductor composition and optional and preferred external semiconductor composition are crosslinked.

Of course, the polymer compositions of the present invention used in one or more cable layers, preferably insulating layers, of the cable of the present invention will have advantageous electrical properties when crosslinked and, preferably, any or all of the mechanical .

The invention relates to a crosslinked power cable, preferably a crosslinked DC power cable, comprising at least one layer, preferably at least an inner semiconductor layer, an insulating layer and a conductor surrounded by the outer semiconductor layer in that order, The invention further provides the use of the polymer composition as defined in the above or the claims, or any preferred ally or embodiment thereof, in at least one layer of the combined HV or EHV DC power cable, preferably at least in the insulating layer. The invention also relates to a crosslinked power cable, preferably a crosslinked DC power cable, comprising at least one layer, preferably at least an inner semiconductor layer, an insulating layer and a conductor surrounded by the outer semiconductor layer in that order, Provides at least one layer, preferably at least an insulating layer, of a crosslinked HV or EHV DC power cable for the production of a polymer composition as defined in the above or the appended claims, or any desired friend or embodiment thereof.

The thickness of the insulating layer of the power cable, preferably a DC cable, more preferably HV or EHV DC power cable, is typically at least 2 mm, preferably at least 3 mm, preferably at least 5 To 100 mm, more preferably from 5 to 50 mm.

How to decide

Unless otherwise stated in the Detailed Description or Experimental Section, the following methods were used for characterization.

% By weight : % by weight

Melt flow index

The melt flow index (MFR) is determined according to ISO 1133 and is expressed in g / 10 min. MFR is an indicator of the fluidity of the polymer, and thus of processability. The higher the melt flow index, the lower the viscosity of the polymer. The MFR is determined at 190 캜 for polyethylene and can be determined at different loads such as 2.16 kg (MFR ₂ ) or 21.6 kg (MFR ₂₁ ).

density

Densities were measured according to ISO 1183-2. Sample preparation was carried out according to ISO 1872-2 Table 3Q (compression molding).

Comonomer  content

a) Quantification of alpha-olefin content in linear low density polyethylene and low density polyethylene by NMR spectroscopy:

The comonomer content was determined by basic quantitative and quantitative 13 C nuclear magnetic resonance (NMR) spectroscopy [J. Randall JMS - Rev. Macromol. Chem. Phys., C29 (2 & 3), 201-317 (1989)]. Experimental parameters were adjusted to ensure a quantitative measurement of the spectrum for this particular task.

Specifically, solution-state NMR spectroscopy using a Bruker Avance III 400 spectrometer was used. A homogeneous sample was prepared by dissolving about 0.200 g of polymer in 2.5 ml of deuterated-tetrachlorethylene in a 10 mm sample tube using a heating block and a 140 [deg.] C rotary tube oven. A proton-separated 13C single-pulse NMR spectrum with NOE (autocorrelation) was recorded using the following acquisition parameters: 90 DEG sweep angle, 4 machining scan, 4096 transient at acquisition time of 1.6 seconds, 20 kHz spectral width, 125 DEG C Temperature, a two-step WALTZ proton separation scheme, and a relaxation delay of 3.0 seconds. Using the following processing parameters, the generated FID was processed: zero-filing up to a 32k data point and apodisation using a Gauss window function; Automatic baseline correction using 5th order polynomials restricted to the 0th and 1st phase and 1st phase and the region of interest.

Amounts were calculated using a simple modified ratio of the signal intensities of representative sites based on methods well known in the art.

b) Comonomer content of polar comonomers in low density polyethylene

(1) a polymer containing more than 6% by weight of polar comonomer units

The comonomer content (wt.%) Was determined in a known manner based on Fourier transform infrared spectroscopy (FTIR) crystals corrected by quantitative nuclear magnetic resonance (NMR) spectroscopy. The following illustrates the determination of the polar comonomer content of ethylene ethyl acrylate, ethylene butyl acrylate and ethylene methyl acrylate. A film sample of the polymer was prepared for FTIR measurements: a film thickness of 0.5-0.7 mm for ethylene butyl acrylate and ethylene ethyl acrylate in an amount greater than 6% by weight, and a film thickness of 0.10 mm for ethylene methyl acrylate Respectively. The film was pressed using a Specac film press at 150 ° C and about 5 tons for 1-2 minutes and then cooled with cold water in an uncontrolled manner. The exact thickness of the obtained film sample was measured.

After FTIR analysis, the baseline of the absorbance mode was plotted against the peak to be analyzed. The absorbance peak of the co-monomer were normalized to the absorbance peak of polyethylene (e.g., split-butyl acrylate or the peak height of the acrylate at 3450cm ^-1 to a peak height of polyethylene at 2020cm ^-1). NMR spectroscopy calibration procedures were performed in a conventional manner well described in the literature described below.

To determine the methyl acrylate content, a 0.10 mm thick film sample was prepared. After analysis, the absorbance at the maximum of the peak for the methyl acrylate of from 3455cm ^-1 subtracted the absorbance of the baseline at 2475cm ^-1 (A _{methyl acrylate} -A _2475). Then, at the maximum absorption peak of the polyethylene peaks at 2660cm ^-1 subtracted the absorbance of the baseline at _{^{2475cm -1 (A 2660 -A 2475)}} . The ratio between (A _{methyl acrylate-} A ₂₄₇₅ ) and (A ₂₆₆₀ -A ₂₄₇₅ ) was then calculated in a conventional manner well described in the literature.

The weight% can be converted to the mol% by calculation. This is well described in the literature.

Determination of the copolymer content in the polymer by NMR spectroscopy

Comonomer content was determined by quantitative nuclear magnetic resonance (NMR) spectroscopy after basic designation (see, for example, "NMR Spectra of Polymers and Polymer Additives", AJ Brandolini and DD Hills, Marcel Dekker , Inc. New York]. Experimental parameters have been adjusted to ensure a quantitative spectrum measurement for this particular task (see, for example, " 200 and More NMR Experiments: A Practical Course ", by S. Berger and Brown ), 2004, Wiley-VCH, Bainheim). Amounts were calculated using simple modified ratios of signal integrations of representative sites in a manner known in the art.

(2) a polymer containing not more than 6% by weight of polar comonomer units

The comonomer content (% by weight) was determined in a known manner based on Fourier Transform Infrared Spectroscopy (FTIR) crystals corrected by quantitative nuclear magnetic resonance (NMR) spectroscopy. The following illustrates the determination of the polar comonomer content of ethylene butyl acrylate and ethylene methyl acrylate. For FT-IR measurements, film samples of 0.05 to 0.12 mm thickness were prepared as described above under method 1). The exact thickness of the obtained film sample was measured.

After analysis by FT-IR, the baseline of the absorbance mode was plotted against the peak to be analyzed. The maximum absorbance of the peak of the co-monomers (e. G., Methyl acrylate and butyl acrylate at 1165cm ^-1 at 1164cm ^-1) subtracted the absorbance of the baseline at 1850cm ^-1 (A _{polar comonomer} -A ₁₈₅₀ ). Then, at the maximum absorption peak of the polyethylene peaks at 2660cm ^-1 subtracted the absorbance of the baseline at _{^{1850cm -1 (A 2660 -A 1850)}} . The ratio between (A _comonomer- A ₁₈₅₀ ) and (A ₂₆₆₀ -A ₁₈₅₀ ) was then calculated. NMR spectroscopy calibration procedures were performed in the conventional manner well described in the literature, as described above under method 1).

The weight% can be converted to the mol% by calculation. This is well described in the literature.

PENT (Pennsylvania Notch  exam)

The resistance to slow crack growth was evaluated using the Pennsylvania Notch Test (PENT) according to ISO 16241: 2005 with some modifications.

A compression molded plaque of each material was prepared according to the following procedure. The granules were heated in a closed mold at 180 캜 for 15 minutes without pressure. The heat was turned off and a nominal pressure of 1.7 MPa was applied for 12.5 hours, during which time the sample and the mold were allowed to cool naturally.

● Dimensions of specimen: 60mm × 25mm × 10mm

● Main notch: 3.5mm depth

● Notch: 0.7mm depth

● Test temperature of specimen: 70 ℃

● Test stress (calculated on the notched cross-sectional area): 2.0 MPa

● Two specimens per material

The time to failure was recorded and the average of the two specimens was calculated.

DC  How to Determine Conductivity

The plaque is compression molded from the pellets of the test polymer composition. The final plaque consisted of the test polymer composition and had a thickness of 1 mm and a diameter of 330 mm.

The plaque is pressure-molded at 130 占 폚 for 12 minutes while the pressure is gradually increased to 2 to 20 MPa. Thereafter, the temperature is raised to reach 180 占 폚 after 5 minutes. The temperature is then held constant at 180 DEG C for 15 minutes during which the plaques are completely crosslinked by peroxides present in the test polymer composition. Finally, the temperature is decreased until the room temperature is reached using a cooling rate of 15 [deg.] C / minute when the pressure is released. The plaque is wrapped in a metal foil immediately after the pressure is released to prevent the loss of volatile components.

Apply a voltage to the test sample by connecting a high voltage power source to the upper electrode. The current generated through the sample is measured with an electrometer. The measuring cell is a three electrode system with a brass electrode. The brass electrode is equipped with a heating pipe connected to a heated air circulator to facilitate measurement at elevated temperatures and to provide a uniform temperature of the test sample. The diameter of the measuring electrode is 100 mm. Place a silicone rubber skirt between the brass electrode edge and the test sample to avoid flashover from the rounded edge of the electrode.

The applied voltage was 30kV DC, which means an average electric field of 30kV / mm. The temperature was 70 占 폚. The current through the plaque was recorded throughout the entire experiment lasting for 24 hours. The conductivity of the insulating layer was calculated using the current after 24 hours.

A schematic illustration of the above method and measuring equipment for measuring conductivity is given in the Nordic Insulation Symposium 2009 (Nord-IS 09), Gothenburg, Sweden, June 15-17, 2009, pages 55-58: Olsson, , &Quot; Experimental determination of DC conductivity for XLPE insulation ").

Methods for determining the amount of double bonds in a polymer composition or polymer

A) IR  Determination of the amount of carbon-carbon double bonds by spectroscopy

The amount of carbon-carbon double bond (C = C) was quantified using quantitative infrared (IR) spectroscopy. Correction was made by predetermining the molar extinction coefficient of the C = C functional group in representative low molecular weight model compounds of known structure.

(N) of each of these groups as the number of carbon-carbon double bonds per 1000 total carbon atoms (C = C / 1000 C) was determined through the following equation.

N = (A x 14) / (E x L x D)

Wherein, A is the maximum absorbance a, E is the molar extinction coefficient (l · mol ^-1 · mm ^-1) of the group, L is the film thickness (mm) is defined as peak height, D is the density of the substance ( g · cm ^-1 ).

The total amount of C = C bonds per 1000 total carbon atoms can be calculated from the sum of N of the individual C = C containing components.

For polyethylene samples, solid state infrared spectra were recorded using an FTIR spectrometer (Perkin Elmer 2000) on a compression molded thin film (0.5-1.0 mm) at a resolution of 4 cm ^-1 and analyzed in absorption mode.

1) polarity Comonomer  A polymer composition comprising a polyethylene homopolymer and a copolymer excluding a polyethylene copolymer containing more than 0.4% by weight

In the case of polyethylene, three types of C = C containing functional groups were quantified, each having characteristic absorption and corrected for the different model compounds, respectively, to produce individual extinction coefficients:

Providing E = 13.13 l · mol ^-1 · mm ^-1 via 910 cm ^-1 based on vinyl (R-CH = CH2): 1-decene [

• Provide E = 18.24 l · mol ^-1 · mm ^-1 via 888 cm ^-1 based on vinylidene (RR'C = CH 2): 2-methyl-1-heptene 2-methylhept-

● trans-vinylene (R-CH = CH-R '): trans-4-decene [(E) - 4-deck yen] E = 15.14l · mol ^-1 through 965cm ^-1, based on · mm ^-1

In the case of a copolymer having a polyethylene homopolymer or less than 0.4% by weight of polar comonomers, a linear baseline calibration was applied between about 980 cm ^-1 and 840 cm ^-1 .

2) more than 0.4% by weight of polarity Comonomer  ≪ RTI ID = 0.0 > polymer < / RTI >

For polyethylene copolymers with more than 0.4% by weight of polar comonomers, two types of C = C containing functional groups were quantified, each having characteristic absorption and corrected for each different model compound to produce individual extinction coefficients :

Providing E = 13.13 l · mol ^-1 · mm ^-1 via 910 cm ^-1 based on vinyl (R-CH = CH2): 1-decene [

• Provide E = 18.24 l · mol ^-1 · mm ^-1 via 888 cm ^-1 based on vinylidene (RR'C = CH 2): 2-methyl-1-heptene 2-methylhept-

EBA:

In the case of poly (ethylene-co-butyl acrylate) (EBA) system, it was applied a linear baseline correction between about 920cm ^-1 and 870cm ^-1.

EMA:

In the case of poly (ethylene-co-methyl acrylate) (EMA) system, it was applied a linear baseline correction between about 930cm ^-1 and 870cm ^-1.

3) Unsaturated Low molecular weight  Polymer compositions comprising molecules

For systems containing low molecular weight C = C containing compounds, they were directly corrected using the molar extinction coefficient of the C = C absorption in the low molecular weight compounds themselves.

B) IR  Mall by spectroscopy Absorbance  Quantification of coefficients

The molar absorption coefficient was determined according to the procedure given in ASTM D3124-98 and ASTM D6248-98. Solution state infrared spectra were recorded using an FTIR spectrometer (Perkin Elmer 2000) equipped with a liquid cell with a path length of 0.1 mm at a resolution of 4 cm ^-1 .

The molar extinction coefficient (E) was determined as l · mol ^-1 · mm ^-1 by the following equation:

E = A / (C x L)

Where A is the maximum absorbance defined as the peak height, C is the concentration (mol · l ^-1 ), and L is the cell thickness (mm).

Three or more solutions of 0.18 mol · l ^-1 of carbon disulfide (CS ₂ ) were used and the average value of the molar extinction coefficient was determined.

Experiment

The Example  And Reference example  Preparation of polymer

All polymers were low density polyethylene produced in a high pressure reactor. With respect to the CTA feed, for example, the PA content may be given in liters / hour or kg / hour and may be converted to another unit using a PA density of 0.807 kg / liter for recalculation.

LDPE1 :

An initial reaction pressure of about 2,628 bar was reached by compressing the recycled CTA and ethylene, intermediate intermediate cooling in a five-stage pre-compressor and two-stage hypercompressor. Total compressor throughput was about 30 tons / hour. In the compressor zone, about 4.9 liters / hour propionaldehyde (PA, CAS No. 123-38-6) was added with about 81 kg of propylene / time as chain transfer agent to maintain a MFR of 1.89 g / 10 min . Here too, 1,7-octadiene was added to the reactor in an amount of 27 kg / hr. The compressed mixture was heated to 157 DEG C in a preheating zone of a forward feed two-zone tubular reactor (inner diameter of about 40 mm and total length of 1200 m). Immediately after the preheater, a mixture of commercially available peroxide radical initiator dissolved in isododecane was injected in an amount sufficient to cause the exothermic polymerization reaction to reach a peak temperature of about 275 DEG C and then cooled to about 200 DEG C. [ The subsequent second peak reaction temperature was 264 占 폚. The reaction mixture was depressurized by a kick valve, and after cooling, the polymer was separated from the unreacted gas.

Characteristics of polyolefin component LDPE1 Basic resin characteristic LDPE1 MFR 2.16 kg, [g / 10 min] at 190 占 폚, 1.89 Density [kg / m ³ ] 923 Vinyl [C = C / 1000C] 0.54 Vinylidene [C = C / 1000C] 0.16 Trans-vinylene [C = C / 1000C] 0.06

The additives used are commercially available:

Ion exchange additive (c): Synthetic hydrotalcite supplied by Kisma Chemicals under the trade name DHT-4V (IUPAC designation: die aluminum hexamagnesium carbonate hexadecahydroxide, CAS No. 11097-59-9).

Peroxide ( PO ): DCP = dicumyl peroxide (CAS No. 80-43-3), commercially available.

Antioxidant ( AO ): 4,4'-thiobis (2,3-butyl-5-methylphenol) (CAS No. 96-69-5), commercially available.

Crush retarder ( SR ): 2,4-diphenyl-4-methyl-1-pentene (CAS No. 6362-80-7), commercially available.

The amount of DCP is given in terms of the content (millimoles) of -O-O-functional groups per kg of polymer composition. This amount is also given in percent by weight in parentheses.

The components of the polymer composition of the present invention and the reference composition (without ion exchange additive (c), crosslinked with the same amount of peroxide as the polymer composition of the present invention), and DC conductivity results are provided in Table 2.

Formulation of polymer composition: The polymer pellets were added to a pilot scale extruder (Prism TSE 24TC), along with a crosslinking agent and additives other than SR, when not present in the pellets. The resulting mixture was melt mixed under the conditions given in the table below and extruded into pellets in a conventional manner.

Where present, peroxide crosslinking agents and SR were added to the pellets in liquid form and the resulting pellets used in the experiment.

Properties of the compositions of the present invention and reference examples: Reference composition The polymer composition of the present invention LDPE 1 ^* 100 100 Ion exchange additive (c) ^** , wt% ppm 0.0023 AO ^** , wt% 0.08 0.08 SR ^** , wt% 0.05 0.05 PO (-OO-millimoles per kg of polymer composition) (wt% of final composition ^** ) 22.8 mmol (0.75% by weight) 22.8 mmol (0.75% by weight) DC  conductivity( fS / m) 26.0 5.7 ^* The amount (wt%) of the polymer component of the table is based on the combined amount of the polymer component (s) used. An amount of 100 weight percent of the polymer component in Table 1 means that the polymer is the only polymer component present in the test composition.
^** The amounts of ion exchange additive (c), peroxide (wt%), AO and SR (wt%) are based on the final composition.

Preparation of the cable: The polymer composition of the present invention was used to make an insulation layer of the power cable.

Power cable extrusion: Cables having three layers were prepared using commercially available semiconductor compositions as inner and outer layers. An intermediate insulating layer was formed with the polymer composition of the present invention. The configuration of the cable was a stranded Al-conductor of 50 mm ² and an insulation layer of 5.5 mm thickness. The inner semiconductor layer and the outer semiconductor layer had a thickness of 1 mm and 1 mm, respectively. The cable line was a Nokia Nokia Maillefer 1 + 2 system, one extrusion head for the inner conductive layer and one for the insulation layer plus the outer semiconductor layer.

The unbridged cable was cooled in water.

When the cable is crosslinked, crosslinking is carried out in a vulcanization tube under nitrogen, followed by cooling in water.

The obtained cable has a low conductivity and shows applicability of the polymer of the present invention as a cable layer, preferably an insulating layer, for a power cable, for example HV DC power cable.

Claims (16)

(a) an unsaturated low density polyethylene (LDPE) homopolymer or a polyolefin which is an unsaturated LDPE copolymer of ethylene with at least one comonomer (s)
(b) peroxide, and
(c) an ion exchange additive in an amount of 0.0001 to 0.045% by weight, based on the total weight of the polymer composition, as an anion exchange additive of hydrotalcite type,
≪ / RTI > The method according to claim 1,
Wherein the polyolefin (a) is an unsaturated LDPE homopolymer or an unsaturated LDPE copolymer of ethylene with at least one comonomer (s) containing vinyl groups,
Wherein the total amount of vinyl groups present in said unsaturated LDPE is greater than 0.05 per 1000 carbon atoms. The method according to claim 1,
Wherein the polyolefin (a) is an unsaturated LDPE copolymer of ethylene with one or more polyunsaturated comonomers and optionally one or more other comonomer (s), wherein
Wherein the polyunsaturated comonomer comprises a carbon straight chain having at least four carbon atoms and at least one non-conjugated double bond located at the terminal. The method of claim 3,
Wherein the polyunsaturated comonomer is selected from the group consisting of 1,7-octadiene, 1,9-decadienes, 1,11-dodecadienes, 1,13-tetradecadienes, Ene, 9-methyl-1,8-decadiene, or mixtures thereof. The method according to claim 1,
Wherein the polyolefin (a) contains vinyl groups in a total amount greater than 0.30 per 1000 carbon atoms. The method according to claim 1,
Wherein the ion exchange additive (c) is an anion exchange additive of a synthetic hydrotalcite type comprising an anionic intermediate layer comprising CO ₃ ^2- anions that can be exchanged. The method according to claim 1,
Wherein the polymer composition comprises its own ion exchange additive (c) in an amount of from 0.0003 to 0.015% by weight, based on the total weight of the polymer composition. The method according to claim 1,
Wherein the peroxide (b) is present in an amount of from -00 to 35 millimoles per kilogram of the polymer composition. CLAIMS What is claimed is: 1. A method of reducing the electrical conductivity of an optionally crosslinked polymer composition comprising a polyolefin optionally crosslinked with peroxide,
(a) an unsaturated low density polyethylene (LDPE) homopolymer or a polyolefin which is an unsaturated LDPE copolymer of ethylene with at least one comonomer (s)
(b) peroxide, and
(c) an ion exchange additive in an amount of 0.0001 to 0.045% by weight, based on the total weight of the polymer composition, as an anion exchange additive of hydrotalcite type,
To produce a polymer composition; and
Optionally, crosslinking the polyolefin (a) in the presence of the peroxide (b)
≪ / RTI > A cable comprising a conductor surrounded by one or more layers,
Wherein at least one of said layer (s) comprises a polymer composition as defined in claim 1. 11. The method of claim 10,
At least a conductor surrounded by an inner semiconductor layer, an insulating layer and an outer semiconductor layer in that order, wherein at least the insulating layer comprises a polymer composition as defined in claim 1. 11. The method of claim 10,
The cable is crosslinked by peroxide (b)
Wherein at least one layer comprises the polyolefin composition as defined in claim 1 before crosslinking. (a) providing and mixing a polymer composition,
(b) applying on the conductor a molten mixture of the polymer composition obtained in step (a) to form at least one layer, and
(c) optionally crosslinking at least the polymer composition of the at least one layer
A method of manufacturing a cable, comprising:
Wherein said at least one layer comprises a polymer composition as defined in claim 1. 14. The method of claim 13,
The method is a method of manufacturing a power cable comprising a conductor surrounded by an inner semiconductor layer, an insulating layer and an outer semiconductor layer in that order,
The method
(a) providing and mixing a first semiconductor composition for an inner semiconductor layer comprising a polymer, carbon black and optionally other component (s); Providing and mixing an insulating composition for the insulating layer; Providing and mixing a second semiconductor composition for an external semiconductor layer comprising a polymer, carbon black and optionally other component (s);
(b) applying a molten mixture of the first semiconductor composition obtained in step (a) on the conductor to form an inner semiconductor layer, adding a molten mixture of the insulating composition obtained in step (a) to form an insulating layer, Adding a molten mixture of the second semiconductor composition obtained in step (a) to form an external semiconductor layer; And
(c) optionally crosslinking at least one of the insulating composition of the insulating layer of the obtained cable, the first semiconductor composition of the inner semiconductor layer and the second semiconductor composition of the outer semiconductor layer under crosslinking conditions
In this case,
Wherein at least the insulating composition comprises the polymer composition as defined in claim 1. delete delete

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